If you,re making your own head stem YZ then you can do anything you like , such as putting the same type bottom seal as the top one just a little bigger on the ID.
OD would have to be the same as the steering head hole .( Bash it in fit )
Fantastic idea Mike - turn it inside out so to speak. There is nothing to stop me doing that, and in fact I don't know why Yamaha didn't do that in the first place. All I need to watch out for is that the steering head bearing goes over the new section. Champion mate.
Fool, I actually already have the new seals, but was thinking of a smarter way to do it - I think Mike has hit on it.
Mainline - I employed a special hand model for those pics
My hands are all knarled up from years of hard physical labour
Now off to look for the right size seals. Perhaps an imperial size could be close to what I'm after. Possibly thinking of making a collar to fit inside the bottom of the headstem to fit a readily available size.
The more I think about it the more flawed I beleive Yamaha's system is. The inside of the bottom seal fits very snuggly (sealing) on the shaft. When you turn the bars the outside of that bottom seal turns against the headstem. Surely the turned shaft would be better to rotate inside the seal as it does at the top
